In a general data transmission technology, the transmitting terminal is configured to transmit the data signal (DATA) and the clock signal (CLK) to the receiving terminal separately; and the receiving terminal is configured to obtain the required data contained in the data signal according to the received clock signal. However, in the transmission path, the transmitted signal may be affected by the RC effects (i.e., resistance, capacitance effect) thereby being attenuated or distorted. In addition, because the data signal and the clock signals are transmitted separately, the two may have different degrees of resistance or capacitance effect; and consequentially, the correctness of the data received by the receiving terminal is also affected.
In order to improve the above problem, before being transmitted by the transmitting terminal, the data signal and the clock signal can be integrated into one piece of serial data, performed by an encoding operation, and then transmitted together. Then, when receiving the serial data, the receiving terminal restores the received serial data back to the required clock signal and have a specific operation according to the frequency of the restored clock signal. Thus, the data signal and the clock signal can have the same degree of resistance or capacitance effect; and consequentially, the correctness of the data received by the receiving terminal is improved.
However, the aforementioned solution still has some disadvantages. First, when the clock signal is being restored, the being-restored clock signal may be affected by noise and cannot be locked in a correct frequency. Second, when the clock signal is being restored, the being-restored clock signal may be affected by noise thereby being locked or null. Third, when the clock signal is being restored, the being-restored clock signal may be locked in a wrong frequency, for example, half or one-fourth of the correct frequency, due to the frequency change of the serial data. The aforementioned three issues may cause that the receiving terminal cannot receive correct data.